1. Field of the Invention
This invention relates to a fuel control system for an engine, and more particularly to a fuel control system for an engine in which fuel supply to the engine is cut during deceleration at different engine speeds depending on whether or not an accessory mechanism such as an air conditioner is operating.
2. Description of the Prior Art
There has been known a fuel control system in which it is determined that the engine is decelerating and fuel supply to the engine is cut when the throttle valve is full closed and the engine speed is not lower than a preset speed in order to improve fuel economy and clean the engine emission. When an accessory mechanism such as an air conditioner is operating, the preset speed is set higher than when the accessory mechanism is not operating, thereby preventing hunting and engine stall.
However, in the conventional fuel control system, there has been a problem that when, for instance, the air conditioner is turned off while the engine is decelerating, that is, when the air conditioner changes from the operating state to the inoperative state while the engine is decelerating, toque shock occurs due to reduction in the engine load and shock occurs due to initiation of fuel cut, which causes uncomfortable vibration of the vehicle body.